An evil creature residing in an anal cavity. Particularly one who creates mass quantities of gasses of a foul smelling nature. When one has unexplained gas attacks, it is said to be due to the presence of a butt goblin.

An insult used to describe a person who is seen to spend a great deal of his/her time with some part of their anatomy inside the asses of other people.

Jill: So what did you do last night Kevin?

Kevin: Well to start the night off I decided to go stick my tongue in Dave's ass, then I spent a couple of hours reaching around inside Lucy's ass, then I played with my own ass for a while, and then I just felt like I needed to assfuck someone so I gave Alex a call.

Any person who performs a surprise ass attack on another, using multiple strong upward punching motions; Man or women who uppercuts anothers behind until bruised and battered, making sure to make goblin, troll or hobbit like noises during the attack.

Anthony: Cover your butt when going up the escalator, Damian is behind you.
Sean: Why should i watch my butt?
Anthony: Because he's a butt goblin!
Sean: Oh, i see.